As semiconductor miniaturization advances, the vertical structure has been complicated, in addition to the reduction in the horizontal dimensions. Therefore, there is an increased need for techniques of flattening the surface of a semiconductor substrate (wafer) and facilitating the processing. Among such flattening techniques, particularly, a chemical mechanical polishing (CMP) technique has become more important.
A polishing apparatus using the CMP technique polishes a semiconductor substrate held by a polishing head, by sliding a polishing pad, while dropping polishing liquid. When the polishing of the substrate is performed, the polishing performance gradually deteriorates, due to abrasive grains and polishing chips adhering to the surface of the polishing pad or due to the change in the property of the polishing pad. Hence, in the CMP, generally, a process called a dressing (conditioning), in which adhering substances on the surface of the polishing pad are removed, the dressing is performed and the surface state is recovered, is performed, during polishing or after polishing.
For example, U.S. Pat. No. 6,508,697 discloses a polishing system including a dresser that includes a supply port for supplying process liquid to a hollow rotation shaft of the dresser and a fixed cover that includes a suction port for sucking the process liquid to the outer circumference side of the dresser. Further, the rotation shaft of the dresser passes through a hole provided on the cover.
However, the hollow structure of the rotation shaft of the dresser as shown in U.S. Pat. No. 6,508,697 has the following practical problem. A contact seal between the hole provided on the cover and the rotation shaft of the dresser deteriorates due to polishing liquid (also referred to as slurry), and therefore, the maintenance frequency increases. For practical use, it is necessary to dispose a rotary joint on the rotation shaft, in order to avoid a hose inserted into the suction port from tangling due to the rotation. Therefore, it is not possible to dispose a cylinder that generates a pressing force on the rotation shaft. Accordingly, a load acting axis is offset horizontally from the rotation shaft, a moment acts on the rotation shaft, and a sliding resistance force increases. Therefore, it is not possible to smoothly control the pressing force.
Further, in the case where the suction port for sucking the process liquid is provided on the outer circumference side of the dresser as shown in U.S. Pat. No. 6,508,697, there is a problem in that it is not possible to sufficiently remove the polishing liquid and debris stuck near the center of the dresser.
It is desired to provide a dressing device, a polishing apparatus, a holder, a housing and a dressing method that make it possible to reduce the maintenance frequency and to smoothly control the pressing force, and that make it possible to enhance the ability of the removal of the polishing liquid and debris stuck near the center.
A dressing device according to one aspect of this technique, a dressing device comprising: a disk that has an opening on an inside, the disk dressing a polishing surface for polishing a substrate; a rotatable holder, the disk being coupled to a lower surface side of the holder, the holder being provided with a first flow passage that passes from a lower surface to an upper surface, the lower surface being inside an outer edge of the opening of the disk; and a housing that is provided with a distance from the upper surface of the holder, the housing being provided with a second flow passage in an interior, the housing being fixed such that an opening of the second flow passage faces the upper surface of the holder, the second flow passage being connected with a supply source and a suction source of process liquid, wherein the process liquid is supplied from the supply source to the polishing surface, through the second flow passage and the first flow passage in order, and the process liquid on the polishing surface is sucked by the suction source, through the first flow passage and the second flow passage in order.
A holder according to one aspect of this technique, a holder that is a component to be used together with a housing fixed in a dressing device, wherein the holder is rotatable, a disk is capable of being coupled to a lower surface side of the holder, and the holder is provided with a flow passage that passes from a lower surface to an upper surface, the lower surface being inside an outer edge of the opening of the disk when the disk is coupled.
A housing according to one aspect of this technique, a housing that is a component to be used together with a holder that is rotatable in a dressing device, wherein the housing is provided with a distance from an upper surface of the holder, the housing is provided with a second flow passage in an interior, the housing is fixed such that one end of the second flow passage faces the upper surface of the holder, and the second flow passage is connected with a supply source and a suction source of process liquid.
A dressing method according to one aspect of this technique, a dressing method that is executed by a dressing device, the dressing device comprising: a disk that has an opening on an inside, the disk dressing a polishing surface for polishing a substrate; a rotatable holder, the disk being coupled to a lower surface side of the holder, the holder being provided with a first flow passage that passes from a lower surface to an upper surface, the lower surface being inside an outer edge of the opening of the disk; and a housing that is provided with a distance from the upper surface of the holder, the housing being provided with a second flow passage in an interior, the housing being fixed such that one end of the second flow passage faces the upper surface of the holder, the dressing method comprising: a step of supplying pure water to the polishing surface, through the second flow passage and the first flow passage in order, during dressing; and a step of sucking process liquid on the polishing surface, through the first flow passage and the second flow passage in order, during the dressing.